Lightweight bathtub and production thereof



Nov. 23, 1954 v. v. DE OLLOQUI ETAL ,6 6

LIGHTWEIGHT BATHTUB AND PRODUCTION THEREOF Filed Nov. 12, 1952 2 Sheets-Sheet I E 5 J 12 7 v5. .7 MP5 I I! II I! '5 II I! II 2412621212 1/ 0e 0H0 26 rl uk iranrl 5 'CarroZZ H Van Harfes z/e 2d?) Nov. 23, 1954 v. v. DE OLLOQUI ETAL 2,695,256

LIGHTWEIGHT BATHTUB AND PRODUCTION THEREOF Filed Nov. 12, 1952 2 Sheets-Sheet 2 :Q 2a nUflUnOfiVlulnI-l :29 5% 2' a; 4 4 g? E 5 7 V E! w J27 van is PS Z/aZejz Zine 1/ 0e OZZoguz' ['arZ A Sfrancz Carr [1 H 2/01: Hdrfesz/eldi United States Patent Dfitice 2,695,256 .Patented Nov. 23, 1954 LIGHTWEIGHT BATHTUB AND PRODUCTION THEREOF Application November 12, 1952, Serial No. 319,992 11 Claims. (Clf154-83) This invention relates to light weight bathtubs or the like receptacles and the production thereof, and more particularly, to a specific glass fiber-polyester laminated bathtub and the production thereof.

As is well known, the ordinary bathtub is a very heavy cast iron receptacle, which is expensive to produce and also to install. In addition, such cast iron bathtubs are extremely diflicult to handle during sh1pment and installation because of their very great weight This excessive weight also prevents or substantially lnn1ts the use of such bathtubs inliving quarters wherein weight of fixtures is a distinct disadvantage, weight cabins, temporary houses, certa1n forms of prefabricated dwellings, and particularly in automobile trailer houses.

gone unsolved, the very great need for bathtubs as units of substantially lighter Weight. The enamel coating, WhlCh is employed for decorative fracture thereof during ordinary wear and tear, and particularly in response to sharp impact. The use of cast iron in the formation of such a shell has, therefore, been considered a necessity, heretofore.

The instant invention provides a unique solution to this lrnportant object of the instant invention to provide an improved light weight bathtub and an improved method of producing the same.

A further object of the instant invention is to provide,

normally flexible polyesters.

It is another object of the instant invention to provide an improved light weight bathtub a cured polyester unsaturated polyester and 4050% for example, in light pigment, 5-15 finely ground Still a further object of the instant invention is to provide an improved method of forming a light weight bathtub that comprises applying a 0.01-0.02 inch coating to a mirrorish convex surface of the contour of the inside of the bathtub, said coating being composed of l0-30% titanium dioxide pigment, 545% finely ground amorphous silica filler, a catalyst mixture of a metal drier peroxide, and 6070% of a polymerizable unsaturated polyester and b that has substantially better heat-insulating properties than cast iron, that is more easily installed than a cast iron bathtub, and that has a highly scratch-resistant smooth glossy finish thereon, and

On the drawings:

Figure 1 is a side elevational view of a light weight bathtub embodying the instant invention, shown in the environment of its installation;

Figure 2 is a sectional elevational view taken substantially along the line II II of Figure 1;

Figure 3 is a sectional elevational enlarged detail view showing the cooperation between the top edge of one side of the tub mold having a coating applied thereto during an initial step in the method of preparing the instant light weight bathtub;

Figure 5 is a top plan view of a glass mat employed in one of the production methods embodying the instant invention for producing the light weight bathtub;

Figure 6 is a Figure 7 is essentially adiagrammatical view showing how a pre-formed impregnated glass fiber shell may be preferred for use in a second production method embodying the instant invention; and

igure 8 is essentially an exploded sectional elevational view showing the mold parts and elements employed in the production method employing the pre-formed shell prepared as shown in Figure 7. s shown on the drawings:

As shown in Figures 1 and 2, the instant light weight bathtub, indicated generally by the reference numeral 10, comprises a suitably formed glass fiber-polyester laminated bathtub shell 11 having upwardly extending 12 and back 13 side walls, and left 14 and right 15 end walls. The back side wall 13 extends upwardly and flares outwardly at 13a to engage and be supported by the bathroom wall W. As will be seen, of the b upwardly and outwardly to respectively, which engage the walls W, W therewith in substantially the wall 13 engages and is supported by the bathroom wall.

The remaining wall, the front wall 12, extends upwardly and near the top thereof at 12a is turned out- This end portion 12b seats firmly in the front groove 16a of an S-shaped elongated metal strip 16 which extends the full longitudinal direction of the shell 11 and arcuate front wall top 12a. The rear groove 16b of the S-shaped strip 16 securely seats the rounded top edge of a supporting panel 17 which extends vertically upwardly from the floor F. 17 is rigidly secured to the floor F, for example, by means of a screw and sprocket assembly 18, and the panel 17 extends the full longitudinal dimension of the shell 11 and upwardly to substantially the height of the arcuate top 12a of the front wall 12. The panel 17 is made of suitably strong structural wood, plywood, heavy-weight laminate or the like material, which is capable of withstanding very substantial downward pressure and which is sufiiciently rigidly secured to the floor F to resist substantial lateral directed forces, so as to afford a certain amount of protection for the front wall 12. The front wall 12 is made of a suitably strong glass fiber-polyester laminate material that is capable of withstanding very substantial downwardly directed forces, and the front wall 12 and panel 17 (by virtue of its supporting engagement with the outer lip 12b of the front wall 12) cooperate to provide very substantial force-resisting support for the top arcuate portion 12a.

In this manner, the top arcuate portion 12a is capable of readily withstanding the ordinary wear and tear during use of the instant bathtub assembly 10, as is particularly capable of withstanding the weight of human beings leaning on or pulling against the arcuate portion 120, while getting in and out of the bathtub 10. It will be appreciated that the panel 17 may be easily installed at the same time the bathtub 10 is installed and the panel 17 may be prefabricated of the desired weight and strength to carry out its particular function just described. It will also be appreciated that in the use and installation of the ordinary cast iron bathtub a structure generally similar to the instant shell structure 11 is employed with a depending wall member, also made of cast iron, which takes the place of the panel 17. In such an arrangement the depending wall member furnishes the sole support for substantially the entire weight of tub, and the top edges of the other walls of the top shell are suitably affixed to the bathroom walls.

The instant top shell 11 is, however, not supported entirely by the panel 17. In fact, because of its light weight and other advantageous features connected therewith, the overall shell 11 is too resilient in character to be supported by the panel 17 alone. It is also necessary to employ a suitable rack or supporting device 18 which is centrally positioned beneath the top shell 11.

As will be seen, the rack 18 consists of a plurality of longitudinally extending generally flat members 19, which are suitably mounted on the curved tops of laterally extending spaced beams 20, which are in turn tied together by tie rods or side boards 21. It will thus be seen that the rack 18 is extends upwardly to support the central portion of the shell bottom, which is itself a generally dish-shaped bottom that is sloped downwardly into the direction of the drain 22 and which becomes decreasingly bowed or dished in shape in the longitudinal direction toward the drain 22 (or the drain end 14 of the shell 11).

A particularly important aspect of the instant invention resides in the particular structural arrangement and composition combination employed in the bathtub shell 11, and the method of fabricating this shell 11. Actually, the shell 11 is composed of a body or structural portion 23 and an integral coating 24, as is best shown in Figure 6. In general, the bathtub shell 11 has a suitably formed integral body 23 of a laminate composed of one part of glass fibers embedded in from one to three parts of normally rigid thermoset unsaturated polyester laminating resin, and it has a smooth-surfaced glossy coating 24 integrally formed upon the body 23. The coating consists essentially of one part of pigment-size filler embedded in two parts of a thermoset unsaturated polyester mixture of equal parts of normally rigid and normally flexible polyester. It is believed, however, that certain of the critical aspects of the instant structure and composition will be thus appreciated from a study of the methods employed in preparing the instant bathtub shell 11.

In one method, which method will be referred to hereinafter as method A, certain steps of which are described or illustrated in connection with Figures 4, and 6, the first step is that of applying the coating 24 to a suitably shaped generally concavo-convex mold form 25, whose the cast 1ron suitably mounted on the floor level and outer surface is shaped to conform with the inside surface of the desired bathtub shell 11. As will be appreciated, the mold form 25 curves outwardly and then sharply downwardly, such as at 25a, along three sides of the base of the mold form 25, in order to correspond to ridges 13b, 14b and side of arcuate side portion of the arcuate portion front wall 12. A suitable spacer support 26 is positioned around the bottom of the form 25 so as to level the same.

The first step in method A is that of applying the desired coating 24 to the outer surface of the mold form 25, as described. A particularly important feature of this process resides in the fact that the outer surface of the mold form 25 is mirror-finished. This is particularly important since it is desired to impart to the ultimately exposed base of the coating 24 a mirror-finished glossy appearance. The mold form 25 is usually coated with a small amount of wax or the like mold lubricant prior to of the coating composition 24. The coating composition 24 is then applied to the mold form spraying unit 27, or by means of any other suitable coating applying devices or processes. Most preferably, the coating is sprayed upon the form 25, to apply a uniformly thick coating 24 having approximately 0.01().02 inch thickness. The consistency of the coating 24 is preferably such that the coating adheres at the location at which it is sprayed upon the form 25 and does not run or gather near the base of the form 25. In the event that the coating may have a tendency to run. slightly, the form 25 may be heated slightly to cause at least a limited amount of preliminary curing to take place in the coating so that the same will adhere at a given location. Also, if a solvent or vehicle is employed to assist in applying the coating to the form 25, then it is usually desirable to heat the walls 25 in order to drive off the solvent and to leave the coating 24 in the desired thickness hereinbefore mentioned.

As previously indicated, the essential ingredients of the coating thus applied include about one part of pigmentsize filler intimately admixed with about two parts of a fluid polymerizable unsaturated polyester mixture, which will be described in detail hereinafter. Most preferably, the pigment-size filler is made up of about one part of finely ground amorphous silica filler, or any other inorganic inert finely ground filler which preferably is white or substantially uncolored; and about two parts of titaniurn dioxide pigment, which has been found to be by fanthe most superior white pigment (and the use of other white pigments, although inferior in most instances, would not necessarily be contrary to the principles of this invention, for certain special uses). As will be appreciated, it is desired to obtain a mirror-finish high gloss type of coating herein and, accordingly, substantially fine, pigment-size filler materials as well as pigments must be used. Actually, the very substantial amount of titanium dioxide employed permits this ingredient to function both as a filler and as a pigment, and the titanium dioxide may be used in proportions Within the range of about l030 weight percent of the coating mixture. The finely ground amorphous silica filler is employed principally to incorporate a sufficient amount of filler in the coating composition to impart the desired high viscosity thereto, as well as the necessary superior strength in the finally cured or hardened coating 24. The amount of such silica filler which may be used may be within the range of about 5-l5 weight percent of the coating composition. (As used herein the terms parts and percent" mean parts and percent by weight, unless otherwise specified.)

The remaining ingredient in the coating composition is the polymerizable unsaturated polyester mixture, with the necessary curing or accelerating catalysts incorporated therein. As previously indicated, in the most preferred coating composition about one part of the silica filler and about two parts of titanium dioxide pigment ar admixed with about six to seven parts of the unsaturate polyester mixture. Actually, however, the proportion may be as follows:

ill-30% titanium dioxide 515 ground silica filler 1 69-70% polymerizable polyester mixture and the nece sary catalyst mixture of ketone peroxide and metal dri As will be appreciated, it is often desirable to include in trace amounts certain other tinting agents which assist in giving a richer white color to the coating, such agents including for example iron oxidepigment. Some of the generally referred to in the art as ethylene glycol-maleate,.or in (i. e. about of pronating resins, the resin is called ethylene glycol-propyl- In general, this polyester is an unsaturated dihydric alcohol-dicarboxylic acid (the unsaturation being furnished by the maleyl radicals therein, which are at least about 60-75 mol percent of the acyl radicals present, the remainder being phthalyl radicals preferably). Often such laminatproportion of a suitably coto assist in the cross-linking process during polymerization; but the general characteristics of these structural or laminating unsaturated polyester resins are those of the true polyester resin system. In other words, the resin is first obtained by the formation of long polyester chain-like molecules which are formed by condensation in the absence of addition polymerization and result in molecular chains having a plurality of unsaturated maleyl radicals therein. such resins are cured, by addition polymerization, the maleyl radicals form cross-links between the chains thus changing the polymer from linear to three-dimensional" and resulting in a rigid thermoset resin.

It has been found, however, that a flexible, substanobtained. In this case the polymerizable polyester is substantially saturated instead of being substantially unsaturated, as just de- Such a resin may be an ethylene glycol-phthalate having perhaps 110 mol percent andpreferably about 25 mol percent of the acid radicals as maleyl radicals and the remainder as phthalyl radicals. The and the structural (or substantially rigid) polyester resins are both commercially available, and are so designated in industry.

In the instant coating composition, it has already been mentioned that about equal proportions of each such structural as a which may be thermoset to form a normally rigid polyester; and the flexible as a saturated polyester which may be cured or set to form a normally flexible ester. In admixture, in the coating composition, it has been found that good results are obtained using about 305[)% saturated polyester and about 7050% unsaturated polyester, and most preferably 40-50% saturated and 605 0% unsaturated polyester.

The catalyst mixture here used is ture of peroxide paste, ganic peroxide and tricresyl phosphate dispersing agent, and a metal drier. The peroxide paste metal drier ratio is about 3-2 2-1. Most preferably the peroxide employed is a ketone peroxide such oxide which effects a minimum final cure of the polyester at the air-exposed surfaces thereof. In the instant composition, most preferably about 3% of paste and 2% of the drier is used.

may be cut and otherwise handled in many respects. Such glass fiber treated with polyester resin, or they the coated mold form 25 and then h laminating polyester of the mats 28, weight of the mat. The polyester laminating resin employed for this purpose is the structural or unsaturated ticles or pigment-size particles, does not subtract substantially from the generally rigid resilience or flexibility. ever, that if certain rod-like filler material lengths, for example, abl

It has also been found, fillers, namely,

interference which results from the 2% of th about 1% After the suitably impregnated glass fiber mats have nch, and the coating has the thickness of about 0.0l0.02 Most preferably, the total thickness of the coating and body combined is approximately 0.08 inch.

with the integrate the body thereby forming 11, by the final a licatron of heat and (low) pressure to the stacked c b ating and impregnated glass fibers to cure the polyesters there- In a second method of forming the instant bathtub shell 11 embodying the instant invention, which method shall be referred to hereinafter as method B, the first step is essentially the same as the first step of method A, as exemplified by Figure 4. In other words, the coating 24 is applied to a suitably formed mold form 25, suitably positioned on base members 26, in substantially the manner hereinbefore described. The resulting coated mold form 24 is thus shown as part of Figure 8.

Instead of employing sheets or glass fiber mats, however, a pro-formed body 23' is formed, in accordance with the showing of Figure 7. in such operation, glass fiber mats, strands or other bulk forms G are fed into a suitable shredder S through the hopper 31 and then through an output conduit 32 into a blower B which effectively blows the chopped glass fibers through a suitable nozzle and against a screen 33 which has been formed in substantially the shape of the ultimate glass fiber-resin impregnated body 23. The air drives the airborne chopped-up glass fiber particles against the screen, so that the air may pass through and the fibers will be held against the screen in the position and thickness desired. This process affords the additional advantage of being able to readily provide extra thickness of glass fibers at specific locations in the body 23. In general, the glass fiber raw material, whether mats, strands or the like, is not cut up by the shredder S into lengths that are shorter than about. one or two inches, since it is desired to have the resulting unique cooperation between the elongated glass fibers and the hardened polyester hereinbefore described. After the glass fibers have been urged against the screen in the manner described, so as to form a glass fiber matting of substantially the shape and thickness ultimately desired in the body 23, a portion or all of the unsaturated polyester resin ultimately to be incorporated in the body 23 is sprayed upon or otherwise added to the glass fibers so as to impregnate the same, and preferably a short preliminary cure of the polyester is effected before the screen is separated from the preformed body 23. In any event, the resin and the glass fibers are caused to cooperate to the extent that they will hold together as a cohesive unit the body 23 formed within the screen 33. The screen 33 is then removed and the preformed body 23' is then positioned above the coating covered mold form 25' and slipped thereover so as to substantially fit the same. Next, an upper mold form 34, which has an inside cavity or base that has substantially the shape desired for the outside surface of the ultimately molded bathtub shell 11, and the top mold form 34 is then brought down against the back of the suitably positioned body 23', so as to urge the body 23 and the coating 24 against the mirrorfinished mold form 25. By the use of the instant matched metal die method B, it is possible to obtain substantially better control of the exact thickness of the various portions of the bathtub shell 11, and also it is possible to effect a substantially greater molding pressure thereby permitting the use of slightly lower molding temperatures. By the use of high molding pressures, it is also possible to more efiectively complete the polymerization of the polyesters in the stacked assembly, particularly if such polyesters have previously undergone a special cure, either for the purpose of causing the coating 24 to adhere more uniformly to the mold form 25 or for the purpose of integrating or holding together the body 23 prior to removing the same from the screen 33.

It will be appreciated that modification may be made in the instant structure, composition and method without departing from the scope of the instant invention.

We claim as our invention:

1. As an article of manufacture, a light weight bathtub having a suitably formed integral body of a laminate composed of one part of glass fibers embedded in two parts of normally rigid thermoset unsaturated polyester laminating resin, and having a smooth-surfaced glossy coating integrally formed upon the body, said coating consisting essentially of one part of pigment-size filler embedded in two parts of a thermoset unsaturated polyester mixture of equal parts of normally rigid and normally flexible polyesters.

2. As an article of manufacture, a tub having a suitably formed integral light weight bathbody of a laminate 8 composed of one part of superimposed glass fiber mats, each substantially coextensive with the body, embedded in two parts of normally rigid thermoset unsaturated polyester laminating resin, and having a smooth-surfaced glossy coating integrally formed upon the body, said coating consisting essentially of one part of finely ground amorphous silica filler, two parts of titanium dioxide pigment and six to seven parts of a thermoset unsaturated polyester mixture of 30-50% normally flexible polyester and 70-50% normally rigid polyester.

3. As an article of manufacture, a light weight bathtub having a suitably formed integral body of a 0.06-0.08 inch thick laminate composed of one part of glass fibers embedded in two parts of normally rigid thermoset unsaturated polyester laminating resin, and having a smooth-surfaced glossy coating integrally formed upon the body and having 0.01-0.02 inch thickness, said coating consisting essentially of one part of pigment-size filler embedded in two parts of a thermoset unsaturated polyester mixture of equal parts of normally rigid and normally flexible polyesters.

4. As an article of manufacture, a light weight bathtub having a suitably formed integral body of a laminate composed of one part of glass fibers embedded in two parts of normally rigid thermoset unsaturated polyester laminating resin, and having a smooth-surfaced glossy coating integrally formed upon the body and having 0.01-0.02 inch thickness, said coating consisting essentially of one part of finely ground amorphous silica filler, two parts of titanium dioxide pigment and six to seven parts of a thermoset unsaturated polyester mixture of 30-50% normally flexible polyester and 70-50% normally rigid polyester.

5. As an article of manufacture, a light weight bathtub having a suitably formed integral body 0.06-0.08 inch thick composed of one part of glass fibers embedded in two parts of normally rigid thermoset unsaturated polyester laminating resin, and having a smooth-surfaced glossy coating integrally formed upon the body and having 0.01-0.02 inch thickness, said coating consisting essentially of one part of finely ground amorphous silica filler, two parts of titanium dioxide pigment and six to seven parts of a thermoset unsaturated polyester mixture of 30-50% normally flexible polyester and 70-50% normally rigid polyester.

6. As an article of manufacture, a light weight bathtub having a suitably formed integral body of a laminate composed of one part of glass fibers embedded in one to three parts of normally rigid thermoset unsaturated polyester laminating resin, and having a smooth-surfaced glossy coating integrally formed upon the body, said coating consisting essentially of 10-30% titanium dioxide pigment, 5-l5% finely ground amorphous silica filler and 60-70% of a cured polyester mixture of 50-60% unsaturated polyester and 40-50% saturated polyester.

7. A method of forming a light weight bathtub, that comprises applying a 0.01-0.02 inch coating to a mirrorfinish convex surface of the contour of the inside of the bathtub, said coating being composed of 10-30% titanium dioxide pigment, 5-15% finely ground amorphous silica filler, a catalyst mixture of a metal drier and a ketone peroxide, and 60-70% of a polymerizable polyester mixture of 50-60% unsaturated polyester and 40-50% saturated polyester; then covering the coating with a layer of glass fibers impregnated with twice their weight of polymerizable unsaturated polyester containing a metal drier-ketone peroxide catalyst mixture; and finally applying heat and pressure to the coating and impregnated glass fibers to cure the polyesters therein.

8. A method of forming a light weight bathtub, that comprises applying a 0.01-0.02 inch coating to a mirrorfinish convex surface of the contour of the inside of the bathtub, said coating being composed of 10-30% titanium dioxide pigment, 5-15 finely ground amorphous silica filler, a catalyst mixture of a metal drier and a ketone peroxide, and 60-70% of a polymerizable polyester mixture of 50-60% unsaturated polyester an saturated polyester; then covering the coatin with a plurality of plies of glass fiber mats each sub stantially coextensive with impregnated with from one to of polymerizable unsaturated polyester containing metal drier-ketone peroxide catalyst mixture; and fin References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,478,165 Collins Aug. 2, 1949 2,489,985 Speight, Jr. Nov. 29, 1949 2,495,640 Muskat Jan. 24, 1950 2,614,058 Francis Oct. 14, 1952 2,617,126 Nebesar Nov. 11, 1952 OTHER REFERENCES Modern Plastics, March 1951, pages -59, 146, 149, 155, 156, The Promise of Reinforced Plastics in e ense." 

1. AS AN ARTICLE OF MANUFACTURE, A LIGHT WEIGHT BATHTUB HAVING A SUITABLY FORMED INTEGRAL BODY OF A LUMINATE COMPOSED OF ONE PART OF GLASS FIBERS EMBEDDED IN TWO PARTS OF NORMALLY RIGID THERMOSET UNSATURATED POLYESTER LAMINATING RESIN, AND HAVING A SMOOTH-SURFACE GLOSSY COATING INTEGRALLY FORMED UPON THE BODY, SAID COATING CONSISTING ESSENTIALLY OF ONE PART OF PIGMENT-SIZE FILLER EMBEDDED IN TWO PARTS OF A THERMOSET UNSATURATED POLYESTER MIXTURE OF EQUAL PARTS OF NORMALLY RIGID AND NORMALLY FLEXIBLE POLYESTERS.
 7. A METHOD OF FORMING A LIGHT WEIGHT BATHTUB, THAT COMPRISES APPLYING A 0.01-0.02 INCH COATING TO A MIRRORFINISH CONVEX SURFACE OF THE CONTOUR OF THE INSIDE OF THE BATHTUB, SAID COATING BEING COMPOSED OF 10-30% TITANIUM DIOXIDE PIGMENT, 5-15% FINELY GROUND AMORPHOUS SILICA FILLER, A CATALYST MIXTURE OF A METAL DRIER AND A KETONE PEROXIDE, AND 60-70% OF A POLYMERIZABLE POLYESTER MIXTURE OF 50-60% UNSATURATED POLYESTER AND 40-50% SATURATED POLYESTER; THEN COVERING THE COATING WITH A LAYER OF GLASS FIBERS IMPREGNATED WITH TWICE THEIR WEITHT OF POLYMERIZABLE UNSATURATED POLYESTER CONTAINING A METAL DRIER-KETONE PEROXIDE CATALYST MIXTURE; AND FINALLY APPLYING HEAT AND PRESSURE TO THE COATING AND IMPREGNATED GLASS FIBERS TO CURE THE POLYESTERS THEREIN. 